Haswell Rig

[PageFault]

Back to cooling

Bad african intarweb is hindering me in finding a Noctua for socket 2011 - have a model number anyone?

edit:

CPU FAN NOCTUA NH-D14 SE2011

How about this? Or this?

CPU FAN NOCTUA NH-D14 SE2011 LP

edit, again

for the build, how's this:

INTEL CORE I7 4820K 3.70G/10M/S2011 NOFAN
CPU FAN NOCTUA NH-D14 SE2011
CORSAIR VENGEANCE PRO 2400MHZ DDR3 16GB KIT CL11 RED X 2
Asus Rampage IV Black Edition socket 2011 boart

Is this adequate, or am I being a piker? Money no problem

[lycorn]

Originally Posted by PageFault

ECM2=F8FC338FC24CE5D099185B29AD7218DD,1,2,501013,-1,250000,25000000,150

Choosong that exponent is not in line with your willingness to find "monster factors". If you look at the "ECM Progress" table, you´ll see that it has just started to be tested in the 30 digits range. I don´t really know how you define a "monster", but I assume a 30 digit (~100 bits) factor wouldn´t qualify as such If you want something around, say, 55 digits (~180 bits) you have a long way to go sweeping through a considerable amount of intermediate ranges - note how many thousands of curves to run to get there...
My point is, if you really want a "monster" go straight to where they may be hiding. If you want something laround 55 digits, your first choice would be M2423 (for the smaller factors the prescribed number of curves has already been run), if around 60 digits pick M2273, and for 65 digits, M1277. Check the table named ECM on Mersenne Numbers with no known factors in http://www.mersenne.org/report_ecm/d...ecmnof_hi=2500.

[PageFault]

I hear you. I still don't know what I am doing and time to read is scarce - try a Director level position, it keeps one extremely busy and work doesn't magically stop at four or something.

I also have a 53000M and a 12000M. I can grab the ones you suggested and run the hell out of them. How's the hardware choices? I can't get the intel site because the patriot act has blocked this country's IP. I am not at all lamiliar with modern choices.

The ECM progress table: I don't know how to interpret it. If I go with yout picks, settings / bounds please ...

[lycorn]

I suggested those exponents because you seem interested in finding VERY large factors. For the ones suggested, you will either give up after a certain time, or, if you are lucky and a factor pops up, find a large one.
The hardware components you mentioned seem quite right. If possible, go for a Noctua cooler.
The ECM Progress Table shows you how far we have gone in testing the numbers in the leftmost column. For factors up to 25 digits long, the B! bound is 50000, and the prescribed number of curves is 280. This means that the program starts by issuing worktodo lines where B1=50000. When the server has already received results for 280 curves, it ups B1 to 250000, which allows to find factors up to 30 digits long. The prescribed number of curves is now 640, and only after receiveng results for this number of vurves will the server start issuing worktodo lines with B1=1000000. Note that, for the same exponent, the curves run with B1=250000 take longer, each one, than the ones run with B1=50000. As we progress, and B1 gets larger, the longer will the curves take.
So the thing is: don´t worry about setting B1 values. The program will do it for you according to the current status of the exponent. If for example you decide to test M2423, the program will send you the following line for your worktodo.txt file: ECM2=xxxxx(AID),1,2,2423,-1,110000000,11000000000,150, because the number is currently being tested for factors up to 55 digits, which implies to use a B1=110000000. The last parameter is the number of curves, that for these small exponents defaults to 150. You may change this parameter, in case you wish to perform a different number of curves.
Hope this helps. Have fun!

[Prime95]

The problem with ECM on small exponents in the 1000 to 10000 area is you need to learn how to run GMP-ECM to do stage 2. This is not a simple task. Given OP's limited time, I'd stick with P-1 using large bounds or ECM on exponents between say 10000 and 100000.

[lycorn]

I´m surprised. I´ve already tried ECM on exponents this small, and the program (Prime95) would happily accept them and run both stages. What am I missing here?

[rajula]

Originally Posted by lycorn

-- What am I missing here?

Both can do it, but GMP-ECM does stage 2 much better than Prime95.

[lycorn]

OK thanks, got it.
Is that the same for stage 1, or may we use one program for stage 1 and the other for stage 2 (in case the savefiles are compatible)?

[rajula]

I guess currently the optimal way to do ECM on special numbers like Mersenne and (generalized) Fermat numbers is to run stage 1 with Prime95 and stage 2 with GMP-ECM. Someone can correct me if there have been advances in software that have changed this.

The Prime95 file after stage 1 can be used in GMP-ECM. See undoc.txt:

Alexander Kruppa wrote some code that allows the output of ECM stage 1 to
be passed to Paul Zimmermann's more efficient GMP-ECM stage 2. This program
is usually faster in stage 1. You can activate this feature by entering
GmpEcmHook=1
in prime.txt. Then select ECM bound #2 between 1 and bound #1. Results.txt
will contain data that can be fed to GMP-ECM for stage 2.

[lycorn]

Thanks a lot. I´ll give it a try.